TimeManager.h

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/*
 * TimeManager.h
 *
 * Part of Fly! Legacy project
 *
 * Copyright 2003 Chris Wallace
 *
 * Fly! Legacy is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 * Fly! Legacy is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 *   along with Fly! Legacy; if not, write to the Free Software
 *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#ifndef TIMEMANAGER_H
#define TIMEMANAGER_H

#include <time.h>
#include "FlyLegacy.h"

// Check that exactly one precision timer method is defined
#if defined(PRECISION_TIMER_PLIB) && defined(PRECISION_TIMER_WIN32)
#error Main/TimeManager.cpp : Multiple precision timer methods defined!!
#endif

#if !(defined(PRECISION_TIMER_PLIB) || defined(PRECISION_TIMER_WIN32))
#error Main/TimeManager.cpp : No precision timer method defined!!
#endif


class CTimeManager {
public:
  CTimeManager ();

  // CTimeManager methods
  void    Prepare (void);
  void    Update (void);
  float   GetElapsedSimTime (void);
  float   GetDeltaRealTime (void);
  float   GetDeltaSimTime (void);

  void    SetUTCDateTime (SDateTime dt);
  void    SetLocalDateTime (SDateTime dt);
  void    SetTimeZoneDelta (bool subtract, SDateTimeDelta delta);
  void    SetTimeZoneOffset (float offset);
  void    GetTimeZoneDelta (SDateTimeDelta &delta, bool &subtract);
  float   GetTimeZoneOffset (void);

  void    SetTimeScale (float scale);
  float   GetTimeScale (void);
  bool    GetPauseState (void);
  void    Pause (void);
  void    Unpause (void);

  SDateTime GetUTCDateTime (void);
  SDateTime GetLocalDateTime (void);
  double    GetJulianDate (void);
  double    GetModifiedJulianDate (void);
  double    GetGreenwichSiderealTime (void);
  double    GetLocalSiderealTime (double lon);

  void    Print (FILE *f);


  // Static methods for general purpose time-related utilities
  static void SunriseSunset (SPosition pos, SDate date, float zenith,
                 STime &rise, STime &set,
                 bool &neverRises, bool& neverSets);

  static int            DaysInMonth (int month, int year);
  static double         JulianDate (SDateTime dt);
  static SDateTime      CalendarDate (double j);
  static SDateTimeDelta SecondsToDateTimeDelta (float s);
  static SDateTimeDelta DaysToDateTimeDelta (double d);
//  static SDateTimeDelta   DateTimeDelta (SDateTime from, SDateTime to);
  static double         DateTimeDeltaToDays (SDateTimeDelta delta);
  static SDateTime      AddTimeDelta (SDateTime dt, SDateTimeDelta delta);
  static SDateTime      SubtractTimeDelta (SDateTime dt, SDateTimeDelta delta);
  static SDateTimeDelta SubtractTime (SDateTime from, SDateTime to);

protected:
  // Master elapsed time (in seconds) since the simulation was started
  float   elapsed;

  // Delta time between calls to Update() in seconds
  float   dRealTime;
  float   dSimTime;

  // Time scale is the realtime scaling factor
  float   scale;

  // Whether simulation time is paused or not
  bool    paused;

  // Local time zone settings
  //  tzDelta   represents number of hours to be subtracted or added to UTC
  //  tzSubtract  indicates whether the delta should be subtracted from UTC
  SDateTimeDelta    tzDelta;
  bool        tzSubtract;

  // "Zero" date/time, i.e. the calendar date and time when the simulation
  //   was started.  This base value is used in conjunction with the simulation
  //   elapsed time to derive the current simulation date/time
  SDateTime epoch;

#ifdef PRECISION_TIMER_WIN32
  // CTimeManager uses the Win32 functions QueryPerformanceFrequency
  //   and QueryPerformanceCounter as its high-resolution counters on
  //   the Windows platform
  float     freq;         // Counter frequency
  LARGE_INTEGER count, prev_count;    // Counter values
#endif

#ifdef PRECISION_TIMER_PLIB
  // Use platform-independent PLIB utility timer
  ulClock *clock;
#endif
};


#endif // TIMEMANAGER_H

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